"Your attachment is too large to send." We've all seen that message at the worst possible moment. PDFs packed with images can balloon to many megabytes, too big for email or upload limits. Compressing a PDF shrinks it down while keeping it perfectly readable. Here's how, and how to pick the right level.
Why do PDFs get so big?
The usual culprit is images. A document full of high-resolution photos or scanned pages carries a lot of data. Compression reduces the size of those images and streamlines the file's internal structure, often cutting the size dramatically without you noticing any difference on screen.
How to compress a PDF (step by step)
- Open the Compress PDF tool and upload your file.
- Choose a compression level: light, recommended, or maximum.
- Click compress.
- Download the smaller file — you'll see how much space you saved.
Compress a PDF now
Shrink your file to fit email limits — and see how much you saved.
Open Compress PDF →Which compression level should you choose?
- Light (best quality): Small size reduction, near-perfect quality. Use for documents where images must stay crisp.
- Recommended: The sweet spot for most files — a big size drop with quality you won't notice losing. Start here.
- Maximum (smallest): The smallest possible file. Best for text-heavy documents or when size matters more than image sharpness.
Tip: Try Recommended first. If the file is still too big for your limit, step up to Maximum. You rarely need to go straight to the strongest setting.
How small can it get?
It depends entirely on what's inside. A scanned, image-heavy document can often shrink by half or more. A file that's already mostly text may compress only a little, because there isn't much excess data to remove. The tool shows you the exact percentage saved so you know what you got.
Frequently asked questions
In short
Compressing a PDF is the quickest fix for the "file too large" problem. Pick the recommended level for most jobs, step up to maximum if you need to, and you'll have an email-friendly file in seconds — with no real loss in readability.